I. F. Golovaneva

Synthesis, structures, and magnetic properties of binuclear carboxylate complexes with NiII and NiIII atoms

The reaction of NiCl2·6H2O with Me3CCOOH and KOH taken in a molar ratio of 1:2:2 in water afforded the nonanuclear antiferromagnetic complex Py2Ni2(Me3CCOOH)2(OOCCMe3)2(μ-OOCCMe3)2(μ-OH2), which apparently contains NiII and NiIII atoms. The complex was isolated by extraction with CH2Cl2, benzene, or hexane. The reactions of this complex with pyridine bases (pyridine (Py), 3,4-lutidine (Lut), and nicorandil (Nic)) gave the adducts L4Ni2(OOCCMe3)2(μ-OOCCMe3)2(μ-OH) (L=Py, Lut, or Nic, respectively). According to magnetic measurements, intramolecular ferromagnetic exchange interactions in these adducts are complemented by intermolecular antiferromagnetic interactions. Pyrolysis of the pyridine adduct in air or under an inert atmosphere in xylene yielded the antiferromagnetic complex Py2Ni2(Me3CCOOH)2(OOCCMe3)2(μ-OOCCMe3)2(μ-OH2), which contains NiII atoms. The structures of all the complexes synthesized were established by X-ray diffraction analysis. The electronic absorption spectra of these compounds are considered.

Role of metal center in reactions of polynuclear nickel(ii) and cobalt(ii) trimethylacetates with 8-amino-2,4-dimethylquinoline

The reactions of 8-amino-2,4-dimethylquinoline (L) (1) with polynuclear nickel(ii) and cobalt(ii) hydroxotrimethylacetato complexes under anaerobic conditions were studied. The nonanuclear cluster Ni9(μ4-OH)3(μ3-OH)3(μn-OOCCMe3)12(HOOCCMe3)4 gave the mononuclear complex Ni(η2-L)(η2-OOCCMe3)2 (2). The tetranuclear complex Ni4(μ3-OH)2(μ-OOCCMe3)4(η2-OOCCMe3)2(EtOH)6 produced the mononuclear complex Ni(η2-L)(η2-OOCCMe3)(OOCCMe3)L (3). At room temperature, the cobalt-containing polynuclear trimethylacetates, viz., the polymer [Co(OH)n(OOCCMe3)2–n]x and the tetranuclear complex Co4(μ3-OH)2(μ-OOCCMe3)4(η2-OOCCMe3)2(EtOH)6, were transformed into the trinuclear cobalt(ii) complex Co3(μ3-OH)(μ-OOCCMe3)4(η2-L)2(OOCCMe3) (4). Meanwhile, at 80 °C these compounds generated the binuclear cobalt(iii) complex Co2(μ2η2-(HN)C9NMe2)2(μ-OOCCMe3)(L)(OOCCMe3)3 (5). The structures of the resulting compounds were established by X-ray diffraction analysis. Compounds 2—4 exhibit the antiferromagnetic spin-spin exchange coupling, whereas compound 5 is diamagnetic.

Synthesis and structure of new dinuclear palladium complex containing no bridging ligands

Oxidation of the mononuclear semiquinonediimine complex [(NPh)(NH)C6H4]2Pd with silver trifluoromethanesulfonate afforded the diamagnetic dinuclear dicationic palladium complex {[(NPh)(NH)C6H4]2Pd}2(O3SCF3)2 with a Pd...Pd distance of 3.267(1) Å. The complex was structurally characterized, and its spectroscopic and electrochemical properties were studied.

Crystal structure of trans*-[PtEnPyNO2(OH,NO2)*]Cl·2H2O

The structure of trans*-[PtEnPyNO2(OH,NO2)*]Cl·2H2O was determined by X-ray crystallography. The crystals are monoclinic, a = 31.185(6)Å, b = 12.198(2)Å, c = 8.432(2)Å, b = 100.8(2)°, Z = 8, space group C2/c, R = 0.031 for 2059 reflections with I > 2σ(I). In the complex cation, the polyhedron of the Pt atom is an octahedron formed by five nitrogen atoms from ethylenediamine (Pt-N(aver.), 2.062(7) Å), pyridine (Pt-N, 2.053(7) Å), two NO2 groups (Pt-N, 2.064(7) Å), and the oxygen atom of the OH group in trans position to the nitro group (Pt-O, 1.999(7) Å). Complex cations, anions Cl−, and crystal water molecules are linked together through a branched system of hydrogen bonds.

Analysis of chiroptical properties of π-allyl complex [Pd(β-pinenyl)Cl]2

Electronic absorption and circular dichroism spectra of the optically active [Pd(β-pincnyl)Cl]2 complex (1) have been studied. The assignment of the bands in the circular dichroism spectrum in the d—d-transition region of complex1 was made within the framework of the one-electron model of optical activity; this assignment is in agreement with the literature data on the analysis of the absorption spectrum of (Pd(allyl)Cl]2. The (1R,2S,3S,5R) absolute configuration was suggested for the optical (+)589-isomer of1 studied.